Spray painting has become widely accepted as an efficient means of applying paint to a surface in many applications. The utilization of spray painting has found wide acceptance in the manufacturing industry for all types of goods. The advantages of spray painting are recognized for other applications such as painting building structures, or other large pieces of equipment which are built on site or even in the repair of large pieces of equipment in the field. In order to accomplish spray painting, it is necessary to provide a suitable apparatus for pumping liquid paint at a high pressure.
The utilization of diaphragm pumps for a portable spray painter has been recognized heretofore. The portable spray painters have encountered certain problems, one of which is the over heating of oil which is the pump liquid in the diaphragm pump when the painter stops spraying, but the pump continues to operate. Furthermore, the portable spray painters have been heretofore of a large size to accommodate a container for the paint and a reservoir for the pump oil. In addition, it has been found necessary to be able to make a quick change of paint color, or type of paint, in certain instances. The known construction of the portable spray painters have not provided for an easy change from one color to another, or one material to another.